Apparatus for forming an encapsulated strip

Abstract

One or more embodiments of the present invention provide an apparatus for forming a continuous strip of a first compound that is encapsulated by a second compound. The apparatus allows the mixture ratio of the first compound to the second compound to vary. The first compound may be a sealant, and the second compound may be a rubber.

What is claimed is: 
     
       1. An apparatus for forming a continuous strip of a first compound A encapsulated by a second compound B, the apparatus comprising:
 a first extruder for extruding a first compound A, and having an outlet connected to a first gear pump; 
 a second extruder for extruding a second compound B, and having an outlet connected to a second gear pump; 
 wherein the outlet of the first gear pump and the outlet of the second gear pump are fed into respective first and second passageways of a nozzle, wherein the first and second passageways are separate from each other upstream of an outlet of the nozzle; 
 the nozzle having an insert for forming the first and second passageways in the nozzle; and 
 wherein the insert has a distal end for positioning at the outlet of the nozzle, wherein the distal end has an elongated flat portion, 
 wherein the insert has a circular cross section at an inlet end that transitions to a rectangular cross section at the outlet forming an elongated flat rectangular portion. 
 
     
     
       2. The apparatus of  claim 1  wherein there are slits located on each end of the elongated flat portion of the insert to facilitate encapsulation of the flow at an entrance to a die at the outlet of the nozzle. 
     
     
       3. The apparatus of  claim 1  wherein the insert is removable from the nozzle. 
     
     
       4. The apparatus of  claim 1  wherein the distal end of the insert is positioned adjacent a die outlet of the nozzle. 
     
     
       5. The apparatus of  claim 1  wherein the insert has a tapered upper surface. 
     
     
       6. The apparatus of  claim 1  wherein the ratio of the first gear pump to the second gear pump may be varied during operation of the system. 
     
     
       7. The apparatus of  claim 1  wherein the elongated flat portion of the insert is positioned at the inlet to a die of the nozzle. 
     
     
       8. The apparatus of  claim 1  wherein the insert has a flat bottom portion forming a channel.